Gmx: not found

GROMACS version: 2020.4
i got this problem

gmx: not found

the code is

for i in 0 .. 35 $
gmx grompp -f nvt_$i.mdp -c em.gro -p -o remd_$i.tpr 
gmx -np 37 -v -deffnm remd -multidir sim1... sim35 -replex 500 >> remd.log

while i installed gromax and tested the command gmx and got

 :-) GROMACS - gmx, 2020.4 (-:

                            GROMACS is written by:
     Emile Apol      Rossen Apostolov      Paul Bauer     Herman J.C. Berendsen
    Par Bjelkmar      Christian Blau   Viacheslav Bolnykh     Kevin Boyd    
 Aldert van Buuren   Rudi van Drunen     Anton Feenstra       Alan Gray     
  Gerrit Groenhof     Anca Hamuraru    Vincent Hindriksen  M. Eric Irrgang  
  Aleksei Iupinov   Christoph Junghans     Joe Jordan     Dimitrios Karkoulis
    Peter Kasson        Jiri Kraus      Carsten Kutzner      Per Larsson    
  Justin A. Lemkul    Viveca Lindahl    Magnus Lundborg     Erik Marklund   
    Pascal Merz     Pieter Meulenhoff    Teemu Murtola       Szilard Pall   
    Sander Pronk      Roland Schulz      Michael Shirts    Alexey Shvetsov  
   Alfons Sijbers     Peter Tieleman      Jon Vincent      Teemu Virolainen 
 Christian Wennberg    Maarten Wolf      Artem Zhmurov   
                           and the project leaders:
        Mark Abraham, Berk Hess, Erik Lindahl, and David van der Spoel

Copyright (c) 1991-2000, University of Groningen, The Netherlands.
Copyright (c) 2001-2019, The GROMACS development team at
Uppsala University, Stockholm University and
the Royal Institute of Technology, Sweden.
check out for more information.

GROMACS is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License
as published by the Free Software Foundation; either version 2.1
of the License, or (at your option) any later version.

GROMACS:      gmx, version 2020.4
Executable:   /usr/local/gromacs/bin/gmx
Data prefix:  /usr/local/gromacs
Working dir:  /home/samar
Command line:


gmx [-[no]h] [-[no]quiet] [-[no]version] [-[no]copyright] [-nice <int>]


Other options:

 -[no]h                     (no)
           Print help and quit
 -[no]quiet                 (no)
           Do not print common startup info or quotes
 -[no]version               (no)
           Print extended version information and quit
 -[no]copyright             (yes)
           Print copyright information on startup
 -nice   <int>              (19)
           Set the nicelevel (default depends on command)
 -[no]backup                (yes)
           Write backups if output files exist

Additional help is available on the following topics:
    commands    List of available commands
    selections  Selection syntax and usage
To access the help, use 'gmx help <topic>'.
For help on a command, use 'gmx help <command>'.

GROMACS reminds you: "The Poodle Chews It" (F. Zappa)

It looks like that GROMACS is not source in the terminal where you run the command


To source GROMACS

source /usr/local/gromacs/bin/GMXRC

If GROMACS is not installed in the default dir, substitute /usr/local/gromacs/ with the appropriate path.
To source GROMACS by default under linux you can add the source command in your .{yourshell_type}_rc file